This invention relates to a letter opener, and more specifically to a letter opener which removes a small portion of an edge of an envelope.
In the field of letter openers, knife-like letter openers are known which slit the flap edge of an envelope. This kind of letter opener can be dangerous because the sharp point of the opener can cause injury through careless use.
Letter openers are also known which cut off a small portion along the length of one of the lateral edges of an envelope. These openers generally overcome the danger of potential injury involved with knife-like openers by enclosing the blade within a body of some sort.
For example, in the device of U.S. Pat. No. 1,214,894, a cutting edge is disposed in a deformable U-shaped body portion. In operation, a letter is inserted into the body against the back wall. The side walls are then pressed together, causing the blade to puncture the envelope and slide through an opening in the opposing wall. The letter is then slid parallel to the back wall, thus cutting off the edge of the envelope. This design has the disadvantage that when pressing the side walls together, they will press against the envelope, making it difficult to move the envelope with respect to the letter opener.
U.S. Pat. No. 1,082,400 discloses a similar device, which uses a guiding upright to guide the envelope, instead of the back wall of the U-shaped body. This device overcomes the above-mentioned disadvantage of the '894 patent by providing a soft filler into which the blade extends during use, which prevents the side walls from pressing against the envelope. However, even the soft filler will cause the blade to dull in time, making the opener unable to cut through an envelope. Furthermore, the guiding upright of U.S. Pat. No. 1,082,400 is too narrow to allow accurate guiding of the device along the envelope.
Envelope opening devices also are disclosed in U.S. Pat. Nos. 4,530,154, 4,360,970, 3,142,119, 3,153,853, and 673,375. These devices are all complex in design and have drawbacks similar to those outlined above.